add missing header file for HTML standard enumeration

Author: striezel

code/bbcode/HTMLStandard.hpp

@@ -0,0 +1,37 @@
+/*
+ -------------------------------------------------------------------------------
+    This file is part of the Private Message Database.
+    Copyright (C) 2025  Dirk Stolle
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ -------------------------------------------------------------------------------
+*/
+
+#ifndef BBCODE_HTMLSTANDARD_HPP
+#define BBCODE_HTMLSTANDARD_HPP
+
+/** \brief Enumeration type to indicate an (X)HTML standard version.
+ *
+ * \brief Currently, it's only used to distinguish between HTML and XHTML.
+ */
+enum class HTMLStandard: bool
+{
+  /// HTML 4.01 Transitional
+  HTML4_01 = false,
+
+  /// XHTML 1.0
+  XHTML = true
+};
+
+#endif // BBCODE_HTMLSTANDARD_HPP